Abstract：
Children with Multisystem Inflammatory Syndrome in Children (MIS-C) can present with thrombocytopenia, which is a key feature of hemophagocytic lymphohistiocytosis (HLH). We hypothesized that thrombocytopenic MIS-C patients have more features of HLH. Clinical characteristics and routine laboratory parameters were collected from 228 MIS-C patients, of whom 85 (37%) were thrombocytopenic. Thrombocytopenic patients had increased ferritin levels; reduced leukocyte subsets; and elevated levels of ASAT and ALAT. Soluble IL-2RA was higher in thrombocytopenic children than in non-thrombocytopenic children. T-cell activation, TNF-alpha and IFN-gamma signaling markers were inversely correlated with thrombocyte levels, consistent with a more pronounced cytokine storm syndrome. Thrombocytopenia was not associated with severity of MIS-C and no pathogenic variants were identified in HLH-related genes. This suggests that thrombocytopenia in MIS-C is not a feature of a more severe disease phenotype, but the consequence of a distinct hyperinflammatory immunopathological process in a subset of children.
摘要：
儿童多系统炎症综合征（MIS-C）可表现为血小板减少症，这是噬血细胞性淋巴组织细胞增生症（HLH）的关键特征。我们假设血小板减少性MIS-C患者具有更多的HLH特征。收集228例MIS-C患者的临床特征和常规实验室参数，其中85（37％）为血小板减少症。血小板减少症患者的铁蛋白水平升高；白细胞亚群减少；ASAT和ALAT水平升高。血小板减少性儿童的可溶性IL-2RA高于非血小板减少性儿童。T细胞激活,TNF-α和IFN-γ信号标志物与血小板水平呈负相关，与更明显的细胞因子风暴综合征一致。血小板减少与MIS-C的严重程度无关，并且在HLH相关基因中未发现致病性变异。这表明MIS-C中的血小板减少症不是更严重疾病表型的特征。而是在一部分儿童中明显的高炎性免疫病理过程的结果。
